Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0013421 (dystonia)
 8,418 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Detailed autopsy findings are reported for a patient with dopa-responsive dystonia genetically related to the dopa-responsive dystonia locus DYT14 on chromosome 14q13. Substantia nigra and locus ceruleus showed a normal abundance of severely hypomelanized dopaminergic neurons and no Lewy body. In the nigra, the reduction of melanin pigment was found to be asymmetric between the two sides and uneven within neurons, and the lateral aspect of the nigra appeared more affected than the medial, in a pattern similar to the neuronal loss in PD. Dopa-responsive dystonia has a unique neuropathologic signature that seems to be independent of its genotype.
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PMID:Neuropathology of a case of dopa-responsive dystonia associated with a new genetic locus, DYT14. 1208 87

Dopa-responsive dystonia (DRD) is a clinical syndrome characterized by childhood-onset dystonia and a dramatic and sustained response to low doses of levodopa. There are at least three causative genes for DRD: (1) the GCH1 gene on chromosome 14q22.1-q22.2, which encodes GTP cyclohydrolase I (GTPCH), the first enzyme in the biosynthetic pathway for tetrahydrobiopterin (BH4; the essential cofactor for tyrosine hydroxylase [THI]), (2) the TH gene on 11 p15.5, coding for the enzyme TH that catalyzes the rate-limiting step in the catecholamine biosynthesis, and (3) an as yet undefined gene on 14q13 (DYT14). In reports on DRD, in which conventional genomic DNA sequencing of GCH1 was conducted in a relatively large number of pedigrees, mutations in the coding region (including the splice sites) of this gene were found in approximately 60% (range: 49-79%) of DRD families. In our series, after conducting additional GCH1 testing (Southern blotting, cDNA sequencing, etc.) and TH analysis, 86% of families with DRD or dystonia with motor delay (an intermediate phenotype between GTPCH-deficient DRD [mild] and GTPCH-deficient hyperphenylalaninemia [severe]) had identifiable GCH1 or (rarely) TH mutations. Up to the present, only one pedigree with autosomal dominant DRD linked to the DYT14 locus has been reported. Neuropathological findings (no Lewy bodies and a normal population of cells with reduced melanin in the substantia nigra) in DRD patients with GTPCH dysfunction were similar to those in a patient with DYT14 dystonia. There have been no reports of autopsied patients with TH-deficient DRD. Neurochemical data suggest that striatal dopamine reduction in GTPCH-deficient DRD is caused not only by decreased TH activity resulting from a low cofactor (BH4) level but also by actual loss of TH protein without nerve terminal loss. This TH protein reduction in the striatum, especially in the putamen, may be due to a diminished regulatory effect of BH4 on stability (rather than expression) of TH molecules or to a dysfunction of TH protein transport from the substantia nigra to the striatum. The extent of striatal TH protein loss may be critical in determining DRD symptomatology and could contribute to gender-related incomplete penetrance of GCH1 mutations in GTPCH-deficient DRD families. Notwithstanding the discovery of the three causative loci for DRD, a therapeutic trial with low doses of levodopa is still the most practical approach to the diagnosis of this treatable disorder. The trial should be considered in all children with dystonic and/or parkinsonian symptoms or with unexplained gait disorders. Analyses of total biopterin and neopterin as well as neurotransmitter metabolites in CSF appear to be useful for the diagnosis of GTPCH-deficient DRD (the major form of DRD) and of TH-deficient DRD (the mild form of TH deficiency). Findings of the precise mechanism of striatal TH protein loss in GTPCH-deficient DRD, the actual status of dopaminergic systems in TH-deficient DRD, and the novel causative gene on the DYT14 locus will better define the pathogenesis of DRD.
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PMID:[Dopa-responsive dystonia: clinical, genetic, and biochemical studies]. 1654 91

Dopa-responsive dystonia (DRD) is a clinical syndrome characterized by childhood-onset dystonia and a dramatic and sustained response to relatively low doses of levodopa. There are at least three causative genes for DRD: 1) the GCH1 gene on chromosome 14q22.1-q22.2, coding for the enzyme GTP cyclohydrolase I (GTPCH) that catalyzes the rate-limiting step in the tetrahydrobiopterin (BH4; the cofactor for tyrosine hydroxylase [TH]) biosynthesis, 2) the TH gene on 11p15.5, and 3) an as yet undefined gene on 14q13 (DYT14). In our series, 86% of families with DRD or dystonia with motor delay (an intermediate phenotype between GTPCH-deficient DRD [mild] and GTPCH-deficient hyperphenylalaninemia [severe]) had identifiable GCH1 or (rarely) TH mutations. Neurochemical data suggest that striatal dopamine reduction in GTPCH-deficient DRD (the major form of DRD) is caused not only by decreased TH activity resulting from a low cofactor level but also by actual loss of TH protein without nerve terminal loss. This TH protein reduction in the striatum (especially in the putamen) may be due to a diminished regulatory effect of BH4 on stability of TH molecules or to a dysfunction of TH protein transport from the substantia nigra to the striatum.
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PMID:[Dopa-responsive dystonia]. 1743 76

Presently, 17 distinct monogenic primary dystonias referred to as dystonias 1- 4, 5a,b, 6-8, 10-13 and 15-18 (loci DYT 1-4, 5a,b, 6-8, 10-13, 15-18) have been recognized. Twelve forms are inherited as autosomal dominant, four as autosomal recessive and one as an X-linked recessive trait. Three additional autosomal dominant forms (DYT9, DYT19 and DYT20) might exist based on linkage mapping to regions apparently different from, yet in close proximity to or overlapping with the known loci DYT18, DYT10 and DYT8. Clinically, this group of movement disorders includes pure dystonias and dystonia plus syndromes. In addition, dyskinesias (paroxysmal dystonias), although phenotypically distinct from classical dystonias, are discussed within this group. In pure dystonias, dystonia is occasionally accompanied by tremor. In dystonia plus syndromes, dystonia as the prominent sign concurs with other movement abnormalities such as myoclonus and parkinsonism. In the dyskinesias, dystonia occurs as a paroxysmal sign in association with other movement anomalies and sometimes seizures. While gross neuropathological changes are absent in most primary dystonias, including the paroxysmal forms, striking morphological alterations are found in some, such as in the X-linked dystonia-parkinsonism syndrome (DYT3). Neuropathological findings at the microscopic level have also been reported in several cases of dystonia 1 and 5, both of which were previously thought to be morphologically normal. One locus, DYT14 had been erroneously assigned, by linkage mapping, in a family with dystonia 5. There are two forms of dystonia 5, one autosomal dominant and one autosomal recessive. These forms are designated here as dystonia 5a and dystonia 5b (DYT5a, DYT5b), respectively. The disease gene has been identified in 10 primary dystonias, seven autosomal dominant (TOR1A/DYT1, GCH1/DYT5a, THAP1/DYT6, PNKD1/MR-1/DYT8, SGCE/DYT11, ATP1A3/DYT12 and SLC2A1/DYT18), two autosomal recessive (TH/DYT5b and PRKRA/DYT16) and one X-chromosomal recessive (TAF1/DYT3). This article summarizes all known aspects on each of the monogenic primary dystonias, including phenotype, neuropathology, imaging, inheritance, mapping, molecular genetics, molecular pathology, animal models and treatment. Suggestions for the diagnostic procedure in primary dystonias are given. Although much is now known about the molecular basis of primary dystonias, treatment of patients is still mainly symptomatic. The only exceptions are dystonias 5a and 5b with their excellent long-term response to L-dopa substitution.
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PMID:The monogenic primary dystonias. 1957 24

Advances in the genetics of dystonia have further elucidated the pathophysiology of this clinically and etiologically heterogeneous group of movement disorders. Currently, 20 monogenic forms of dystonia, designated by the acronym DYT, are grouped as 1) pure dystonias, 2) dystonia-plus syndromes, and 3) paroxysmal dystonias/dyskinesias. We summarize recently discovered genes and loci, including the 1) detection of two primary dystonia genes (DYT6, DYT16), 2) identification of the DYT17 locus, 3) association of a dystonia/dyskinesia phenotype with a gene previously linked to GLUT1 (glucose transporter of the blood-brain barrier) deficiency syndrome (DYT18), 4) designation of paroxysmal kinesigenic and nonkinesigenic dyskinesia as DYT19 and DYT20, and 5) redefinition of DYT14 as DYT5. Further, we review current knowledge regarding genetic modifiers and susceptibility factors. Because recognizing and diagnosing monogenic dystonias have important implications for patients and their families with regard to counseling, prognosis, and treatment, we highlight clinical "red flags" of individual subtypes and review guidelines for genetic testing.
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PMID:Genetics of primary torsion dystonia. 2042 35

Dystonia represents the third most common movement disorder in humans. At least 15 genetic loci (DYT1-15) have been identified and some of these genes have been cloned. TOR1A (formally DYT1), the gene responsible for the most common primary hereditary dystonia, encodes torsinA, an AAA ATPase family protein. However, the function of torsinA has yet to be fully understood. Here, we have generated and characterized a complete loss-of-function mutant for dtorsin, the only Drosophila ortholog of TOR1A. Null mutation of the X-linked dtorsin was semi-lethal with most male flies dying by the pre-pupal stage and the few surviving adults being sterile and slow moving, with reduced cuticle pigmentation and thin, short bristles. Third instar male larvae exhibited locomotion defects that were rescued by feeding dopamine. Moreover, biochemical analysis revealed that the brains of third instar larvae and adults heterozygous for the loss-of-function dtorsin mutation had significantly reduced dopamine levels. The dtorsin mutant showed a very strong genetic interaction with Pu (Punch: GTP cyclohydrolase), the ortholog of the human gene underlying DYT14 dystonia. Biochemical analyses revealed a severe reduction of GTP cyclohydrolase protein and activity, suggesting that dtorsin plays a novel role in dopamine metabolism as a positive-regulator of GTP cyclohydrolase protein. This dtorsin mutant line will be valuable for understanding this relationship and potentially other novel torsin functions that could play a role in human dystonia.
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PMID:Dtorsin, the Drosophila ortholog of the early-onset dystonia TOR1A (DYT1), plays a novel role in dopamine metabolism. 2202 56